


Fire-Hollowed Souls

by bouquetofwhoopsiedaisies



Category: Voltron: Legendary Defender
Genre: Alternate Universe, Battle, Blood, Demonic Possession, Demons, Implied Sexual Content, Japan, Japanese Mythology & Folklore, Kuron isn't an enemy he's just trying his best... even if he makes a bad decision, M/M, Swords, The only character death is nameless OCs, Using your new bae to stab your enemies... and other revelations by Shiro, Violence, Youkai, but consensual demonic posession if that helps, demon sword Keith, featuring a smattering of obscure history because I am a nerd, it is still rather violent though
Language: English
Status: Completed
Published: 2018-08-22
Updated: 2018-08-22
Packaged: 2019-06-30 23:27:47
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 3,773
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15761910
Author URL: https://archiveofourown.org/users/bouquetofwhoopsiedaisies/pseuds/bouquetofwhoopsiedaisies
Summary: Shiro, one of the last surviving members of his clan, stumbles upon an abandoned castle while fleeing his pursuers.  With his enemies closing in on him, few options for survival, and only one arm, he accepts the help of a demon trapped in a sword for a century, in an encounter that will change the course of both of their lives forever.(forakira-ni-nekora)





	Fire-Hollowed Souls

**Author's Note:**

  * For [nekora](https://archiveofourown.org/users/nekora/gifts).



> Small brain: make the enemy clan the Galra  
> Big brain: _base the warring clans on super-obscure local history of a little-discussed region instead!_ >:D
> 
> (I like the Galra too much to vilify them, even off-handedly, and once it was requested to not vilify the Galra as a whole, I immediately decided to take that and run off into the sunset with it. And I do love me some obscure local history. Rural Northern Japan Shiro headcanon, FTW! Let it be known that Tsugaru is the coolest region in Japan B) ~~actually temperature-wise the Nanbu side is cooler but STILL~~ )
> 
> Forewarning, I am aware that the word-order/translation of Keith’s sword name is far from perfect. I spent waaay too long focusing on one little detail of the story that eventually I was like, you know what, just move on, it is good enough for the plot point that it serves even if it isn’t perfect. I really just wanted something that made a reasonable amount of sense and whose letters (excluding particles because that would be a nightmare) spelled out K-E-I-T-H. Granted, someone in unspecified-late-Bakumatsu-early-Meiji-period probably wouldn’t think of it in terms of English letters, but I tried working something out from キース (“kiisu”) and just didn’t like any of the things I came up with. Sooo, fic magic waved over it, let’s just move on to the actual story.

_Cold… everything was cold, and dark, and quiet.  He was almost there, he almost had enough power to manifest a body for himself.  It had been so long -- nearly one hundred years -- since he had felt the warmth of a hand grip around his hilt.  And yet, he couldn’t decide which was worse; the chill of the breeze rustling through the empty castle, not even strong enough to disturb the century of dust that had settled over the long-abandoned sword… or the heat of a warrior’s hand wrapping around him in battle, thrusting his wickedly sharp blade into their enemies and scraping him against bone and flesh without a care for him.  He was a weapon of war, crafted for cruelty, and he knew nothing else. Slowly, over the years, he gained sentience, absorbing the lives he was forced to take for his own. With every kill, he grew stronger, and soon he was strong enough to take possession of the hands that dared to wield him for their own selfish gain. He turned against them and took their lives too, until people started muttering that the old castle on the hill was cursed, and the abandoned place fell into ruin.  And so he sat, for untold scores of years, biding his slowly-growing power even as he gathered more dust along his pristine steel blade. As the sun set behind the mountains, the last dregs of blood-red sunlight glinted off his blade and he felt his consciousness stir. He would have smiled, had he lips and a face of his own. He could feel it; another battle was coming. Hopefully, it would be the last in this form._

~~~~~~~

Shiro leaned his back against a wide cedar tree to catch his breath as he pulled out what was left of his water supply.  He drank sparingly, just enough to wet his parched throat without properly quenching his thirst, but he couldn’t risk it.  He was making good time, considering his condition, but he still had a very long way to go before he could rest safely.

He looped the cord of the gourd water bottle through his belt and attempted to clumsily tie it using his one hand and pinning the cord against his hip.  After a few minutes, he huffed in frustration and gave up, settling for carrying the gourd in his hand. At the very least, he supposed, he could whack it across an enemy’s face, if it came to it.  

Legs aching in protest, Shiro pushed away from the tree and set off again.  Night was falling quickly, and he needed to keep moving. The sun was already low in the sky, throwing light through the trees and bathing the forest in an eerie red glow, almost like the land was drenched in blood and fire.  Much like his home had been, when he was forced to flee.

Shiro looked down at the bandaged stump that used to be his right arm, a cocktail of rage and grief swirling in his gut as the memories rushed forward.  The screams, the clash of steel against bone and stone, the fires birthed from flaming arrows consuming the castle… His father, stabbed to death nearly right in front of him, close enough that Shiro could see the light leave his eyes but far enough that by the time Shiro got to the spy and killed him, his father was already dead.  His father’s retainer shoving him away through a secret door, begging him to flee as the last of his family’s line… the escape, the ambush as he crept through the apple orchards that dotted the land around their domain, the fight that he just barely escaped with his life from, and in the process lost his arm… pain, blinding pain on top of the grief he was already drowning in, and red blood staining red apples on the ground as he fell…

By some small fortune (if he had any left), he had managed to stagger to the castle at the nearby city, also in his family’s domain.  The Kuroishi castle was much smaller than their clan’s main castle in Hirosaki (itself much smaller than the grand castles of wealthy domains further south), but it was well-armed and ruled by Shiro’s half-brother.  A kind, well-intentioned man, he was affectionately known as Kuron, due to his status as lord of Kuroishi and his proclivity for slipping the local dialect into his speech, particularly the - _n_ and _-ndabe_ endings.  From the moment Shiro pounded on the heavy gate, Kuron was quick to support him himself while shouting for their doctor, with little care that Shiro was getting blood all over his clothes as he ushered him into the castle.  There, they treated his arm and managed to keep him from dying, but he knew he couldn’t stay long.

_“Leaving would be foolish.”  Kuron told him, crossing his arms in the sleeves of his haori.  “You can’t expect to get far, with only one arm.”_

_“I’ll just have to make do.”  Shiro shot back, glaring at the uncooperative cloth obi he was attempting to tie around his own waist with only his left hand._

_Kuron sighed and came forward to help him tie the obi.  “I’m sorry we can’t offer you better medical care at the moment.  We have only one doctor here. But I have made arrangements.”_

_Shiro paused.  “What arrangements?”_

_Kuron pushed a hand through his hair, looking away sheepishly.  “You know we don’t stand a chance, Shiro. The Nanbu clan far outnumbers us, and they have backing from Morioka that we don’t have… it’s no easy feat, taking down that castle, but they did it, and they’ll do it here too, unless…”_

_“What did you do?”  Shiro’s voice hardened, eyes narrowing in suspicion._

_Kuron sighed.  “I’ve negotiated with the Nanbu.  Compliance in return for medical care for the survivors of the attack, and limited administrative power moving forward.”_

_Shiro stepped back, turning a cold glare on his brother.  “You’re a coward.”_

_“I’m saving our lives, and the lives of our people.”  Kuron gave him a level look. “We can’t win against them.  It was this or have them raze our villages to the ground and slaughter our citizens.”_

_“You mean like how they slaughtered our father?”  Shiro snapped. “While you were sitting here in your castle, comfortable as can be?”_

_Kuron’s eyes flashed, and Shiro remembered that his kind brother could turn, if pushed enough.  Quick as it had come, though, the anger cooled and hardened. “I couldn’t have predicted that ambush any more than you could have.  By the time you got word to us, there was nothing we could have done. All I could do was try to salvage what’s left of the situation through negotiating.”_

_Shiro looked away, furious although he knew Kuron spoke the truth.  Still, he wouldn’t just lie down and wait for their enemies to take him away.  As heir to the Tsugaru clan, he doubted they would let him live. Kuron would be reasonably safe, being only the head of the sub-domain.  “When are they coming?”_

_“Tomorrow or the next day at the latest.”  Kuron replied, regret heavy in his voice._

_Shiro nodded and got to his feet.  “Then I am leaving.” A mere day’s head-start wasn’t ideal, but neither was embarking on a journey with one arm._

_Kuron opened his mouth as if to protest, then sighed in resignation.  He turned to the servant who had brought medicine and bandages for Shiro’s arm.  “Outfit him with traveling clothes and as much food and water as he can carry.”_

_“You’re not going to stop me?”  Shiro asked him as the servant nodded and hurried away._

_Kuron lifted his hands in a shrug, the corner of his lips lifting in a wry smile.  “When have I ever been able to, brother?”_

And so he had left under the cover of the early morning darkness, heading north.  It was a long-shot, but he figured if he could make his way up the remote peninsula, perhaps he could pay off a fisherman in a coastal village for a boat and… somehow sail one-armed across the strait to Ezochi, where they might allow him to take refuge.  Surviving the journey would be incredibly difficult, but what choice did he have? The enemies pursuing him would surely kill him, if they found him.

Shiro swallowed thickly and picked up his pace.  The forest was too quiet; his pursuers must have been close behind.  Up ahead, he spotted an old, crumbling castle on the hillside. He was not sure how far up the peninsula he was -- Aburakawa?  Uchimanbe? What other castles were around here? -- but whatever this castle once was, it seemed to have fallen into ruin. He started climbing the hill.  Hopefully, he could hide here until it was safe to continue.

Just as he was making his way across a small break in the trees in front of the castle ruins, a shout echoed from the forest and a jolt of fear ran through him.  They had spotted him. Shiro bolted into the castle, praying he might be able to lose them in the rubble. He should have waited until the last of the sunset faded from the sky and he had the cover of darkness, but there was nowhere to hide and they would have come upon him before he could have made it to the castle undetected.  As he shoved an old, heavy door shut behind him, he could hear shouting and footfalls against the stone, and he knew that a fight was inevitable, now.

Shiro ran through the quickly-darkening castle as the soldiers behind him pounded on the door and shouted something about pulling down that post to use as a battering ram.  He had to hide, or find some way to defend himself… He had a knife from Kuron, but it would do little good against swords. He wished he had his katana, but he had been forced to leave it when he fled his castle, and he wasn’t sure he could use it with only his left hand, anyway.  

A glint of light caught his eye as Shiro ran past a doorway.  A sword, naked blade rosy with dust and the light of the setting sun, sat propped against a hunk of stone against the far wall.  An almighty _crack_ echoed from downstairs as the soldiers broke through the front door, and Shiro leapt forward and closed his hand around the hilt of the sword, desperate for a weapon.  

Cold doused him and time seemed to slow, his movements like wading through tree sap.  His stomach lurched sickeningly, like he had suddenly fallen into a deep, dark pit filled with an ancient, dangerous energy.  What _was_ that?  The sword… he realized.  He should let go of the sword…

 _You can’t_ .  A voice wrapped around his mind like frost creeping over dying leaves.   _How would you defend yourself, without me?  You’ll probably die anyway, even if you try and wield me.  I can tell you’ve lost your dominant hand._

It was true.  He couldn’t fight like this; they would disarm him in a minute, send the sword flying out of his remaining hand with only one strong blow.  

 _Unless you let me help you._  The voice went on.

The words made Shiro pause.   _...Help how?_  He asked, not even sure who he was asking.

 _Give yourself over to me, let me defend you…_ the voice seemed to surround him, growing closer and closer even as he heard his enemies coming closer too.   _Let me forge you a new arm that can wield me easily._

 _What do you want?_ Shiro frowned.  There had to be something he -- they?  It? -- wanted in return.

 _Just the taste of your enemies’ blood…_ the voice curled around him, deathly cold.  

Shiro shivered, but he could already hear thunderous footsteps charging toward the room he was in.   _Alright_.

The coldness sharpened, giving Shiro the impression of a toothy smile even though he could see no face.   _Then open your mind to me._  

Shiro took a deep breath, the cold air burning his lungs worse than the frigid winters that swept through the mountains, and he closed his eyes.  The coldness flooded in immediately, rushing through him like he had just plunged into a frozen lake, and the sensation raced up his left hand and arm, across his chest, down his right arm…

Shiro opened his eyes and gasped; there was a glowing arm and hand reaching from where his stump ended, made of twisted strands of burning red and icy aquamarine.  He could _feel_ it, almost like it was an extension of his own body, fingers curling and eager to wrap around a sword hilt.

 _Give me my blade_.  The voice commanded over the shouts that were growing nearer.  Shiro compiled at once, passing the sword from his left hand to the glowing right.  It fit between his hands like it was made for them, despite one being flesh and the other demonic energy.  

Something overtook him at once, and Shiro felt his body move without his will.  It whirled around and lunged toward the soldier than burst through the door, slicing his head clean off his shoulders with one strike.  Shiro’s mind recoiled at the sight, but the voice holding his body captive chuckled lowly. _Almost there… one or two more, I think…_

 _One or two more what?  What are you talking about?_ Shiro asked.  

 _You will see_.  The voice dismissed him and took control again, charging forward to attack the next soldiers that ran through the door.  More of piled in, yelling and brandishing their own swords, but Shiro -- or rather, the thing possessing him -- cut them all down spectacularly.  Soon, four bodies littered the floor, blood painting them and the stones like spilled sunset.

 _Finally…_ The voice sighed, energy buzzing and crackling around them.  Before Shiro could ask what was going on, the force that had wrapped around him and taken hold of his body tore itself away, the glowing arm ripping itself off his shoulder.  Shiro cried out in pain and staggered back, feeling like part of his very soul had been torn from his body.

When he opened his eyes, he found a man standing in front of him, naked and covered in blood, and holding the sword in his hand.  There was something otherworldly about him. Maybe it was the coals burning in his strange, amethyst bright eyes that watched Shiro with a curious hunger from between his overlong, dark hair.  Maybe it was that smile, a little too cold and sharp considering he was covered in blood. Maybe it was the way he held the sword, like it was an extension of himself. Then again, Shiro realized, it probably was.  

The man looked down at his hands, opening and closing the fingers that weren’t wrapped around the hilt of the sword.  “Finally… after a century of waiting and biding my time, I have a body of my own…”

Shiro felt his heart stop.  “You… you tricked me. You just used my enemies to get yourself a body…”  And now, would he leave Shiro to be killed? Or kill him as well?

The man cast him a level look.  “I meant what I said. I will defend you.  I can just do it with my own hands, now.” He lifted the sword and faced the door.  “I have this form because of you. I will not allow harm to come to you on my watch.”  He tilted his chin down, grinning. “I might be a murderous blade, but I’m not without honor.”

“Who are you?”  Shiro asked. “ _What_ are you?”  

The man looked back at him over his shoulder.  “ _Ken-no-eikyuu-ni-iouno-te-kara-hanasenai_ .”  He said.  “ _The eternally sulfurous blade that cannot be released from one’s hand_.”

Shiro blinked.  “Yeah, you need a nickname.”  

Ken-no-eikyuu-- ...the man stared at him, taken aback.  “A what?”

“A nickname.  Something shorter.”  Shiro said, getting to his feet.  “Like, my name is Shirogane Takashi Tsugaru-no-kami, because of my status, but people just call me Shiro.”  

The man stared at him.  “I don’t have something like that.  People just call me ‘ _the eternally sulfurous blade that cannot be released from one’s hand_ ’.  Or sometimes, ‘ _cursed blade_ ’.”  He frowned.  “It’s not like I _asked_ to be cursed…” He grumbled.

Shiro thought about it.  If they just put the first part of each word together, excluding the particles, then… “What about ‘Keith’?”  It was strange, as a name (sounded foreign), but admittedly, the man himself was quite strange, having manifested from a demonic sword.  

The man tilted his head thoughtfully.  “Keith…” He nodded, smiling. “I think I like it.”  

Shiro opened his mouth to say something, but the words were cut off by a shout of “Look out!” as another Nanbu soldier came charging around the corner.  Lightning quick, Keith whirled around and spun, slicing the man’s head off and getting a fresh splatter of blood across his naked chest.

“You should sit down.”  Keith told Shiro over his shoulder, far too casual to have just decapitated someone.  “I stole a decent chunk of your energy when I left your body.”

“Great.”  Shiro muttered.  It was true, his limbs felt heavy and weak.  

“You’ll replenish it.  But I can’t.” Keith was remarkably candid as he stabbed another soldier and tossed the body aside.  

“Then how will you stay alive?”  Shiro asked.

Keith didn’t answer, but he shot him a sly grin that made something strange and warm curl deep in Shiro’s gut.  

~~~~~

By the time the sun had fully set, every one of Shiro’s pursuers had fallen to Keith’s blade.  The man was drenched in blood, and Shiro himself was not much better (battle was messy, especially in such close quarters).  To make matters worse, the last of the sun’s glow had disappeared from the sky, leaving Shiro blinking and squinting into the darkness of the dilapidated castle room.  With the adrenaline wearing off, and Keith having “stolen his energy”, whatever that meant, Shiro was slumped against a pile of stone rubble, exhaustion tugging at his bones and eyelids. 

He heard a soft scuff in front of him and opened his eyes just as a ball of blue light flared to life, illuminating Keith’s face as he crouched before him.  The ball of _onibi_ \-- demon fire -- floated just above his outstretched hand, flickering eerily in the dark.  “Come on. We’ll find a different part of the castle to spend the night in, then in the morning, we’ll leave this place.”  Keith told him.

Shiro accepted the hand he offered him, their grips slippery with spilled blood.  “And go where?”

Keith shrugged, the ghostly light dancing off his bare skin as he lifted and dropped his shoulder.  “Wherever it is you’re going.” He lifted his sword and sliced through an ancient wall until there was room to crawl through it.  “I imagine you have more enemies out there. I’ll slay all of them.”

“Why?”  Shiro asked, following him outside.  “What are you looking to get, in return?”  His footing slipped on a stray piece of enemy armor and he stumbled, nearly pitching forward, but Keith caught him against his chest.  

Keith’s features looked even more eerie in the flickering demon fire.  “You.”

Shiro froze.  “Me?”

Keith hummed and backed Shiro up against the wall of the castle.  “You.” He lifted a hand and brushed cold fingers across Shiro’s cheek, leaving a streak of red that chilled his skin.  “I laid abandoned in that castle for nearly a century. It has been a long time since I have felt as warm as I do when I touch you.”  His hand slid around to the back of Shiro’s neck, palm icy cold against his nape, and Shiro realized that Keith was pressed close to him and still very, very naked.  “I can form a right hand for you, or take this form, and slay your enemies for you. But to do that, you have to allow me access to your body.”

Shiro’s scalp prickled, but he couldn’t tell if it was from his words of the coldness of the body pressed against him.  He also couldn’t tell if it was trepidation or excitement that he was feeling. “Access?” He questioned.

Keith arched an eyebrow.  “To your arm, most certainly.  And your muscles. Guiding control over your spirit would be nice, too, otherwise we can’t fight cohesively together, though you will never lose control of your mind.”  He paused, his eyes flicking downwards as the corners of his lips twitched up. “I wouldn’t say no to a different sort of access between battles, either.” His voice dropped to a low purr.  

Shiro swallowed thickly, trying very hard to keep his decisions coming from his head and not from between his legs.  Maybe he was crazy, for considering this -- Keith was a demon who had just killed an entire hunting party right in front of him, and did he mention he was a _demon_?? But… demon or not, Shiro wouldn’t be alive if not for him.  And he was certainly attractive, for a demonic entity.

Steeling himself, Shiro lifted his hand and pushed his fingers through dark, blood-damp hair, cupping Keith’s cheek for a moment before leaning in to kiss him.  He was cold and tasted like iron and frost, but Shiro found he liked it. He felt Keith grin against his lips and slide a hand down his chest, slipping it between the front of his kimono.  

Shiro jumped slightly and closed his fingers around the slim, strong wrist.  “We should bathe first. And get you something to wear. And get inside.”

Keith pulled back to give him a puzzled look, then realized Shiro’s hesitation and rolled his eyes.  “Humans… such an aversion to blood...”

“So you don’t have a problem being nude and soaked in blood?”  Shiro asked.

Keith lifted the sword in his hand and eyed the length of it critically, letting the moonlight glint off the naked bloodstained blade.  “I’m used to it.” He shrugged. “There’s a river nearby. We can wash there.”

“Thank you.”  Shiro followed him.  He glanced at the way Keith was carrying his sword in his hand, blade open to the air.  “Do you have a sheath? To keep your sword in?”

Keith’s eyes dropped to the katana.  “Not that one.” He smirked.

“You… have another sword?”  Shiro asked, confused. Where was he keeping it?  

Keith shot him a wicked-sharp grin, his gaze dropping suggestively.  

Shiro’s ears burned bright red, and for once, it was his own blood and not that of his enemies.  

**Author's Note:**

> BONUS SCENE, LATER:  
> Shiro: “You’ve gotta stop referring to your dick as a ‘sword’...”  
> Keith: “...Shiro my entire body is a sword. That’s my whole thing.”
> 
> (wait until he figures out their names put together sound like “sheath”... ~~even though that word-play doesn’t work the same in Japanese but shhh just pretend it would…~~ ) 
> 
> I’m sorry I didn’t get to all the details of your prompt, Akira! This itself turned out longer than I planned, but I adored the prompt too much and had to do something at least (^.^)


End file.
